Laser-induced level shifts and splittings in multiphoton pair creation

Using numerical solutions to the Dirac equation, we examine the role of energy shifts on the energy spectrum of created positrons in the laser-induced electron-positron pair-creation process in the presence of a highly charged model nucleus. We suggest that at those laser intensities, where the created electrons can be captured by the nucleus, the inclusion of the field-induced energy level shifts is crucial to predict correct positron energy spectra, especially close to the threshold for this process with regard to the laser frequency. For the interesting case where the laser frequency is tuned to the bound state energy differences, the coherence associated with possible electronic Rabi oscillations is transferred to the generated positrons, leading to new split peaks in their energy spectrum.

Automated summary

In this study, numerical solutions to the Dirac equation are used to investigate the influence of energy shifts on the energy spectrum of created positrons in the laser-induced electron-positron pair-creation process with a highly charged model nucleus. The results suggest that including field-induced energy level shifts is crucial for predicting correct positron energy spectra, especially when the laser intensity allows for electron capture by the nucleus. Additionally, when the laser frequency is tuned to bound state energy differences, coherence from possible electronic Rabi oscillations is transferred to the generated positrons, resulting in new split peaks in their energy spectrum.